Composite molded article having two-layer structure

Abstract

The present invention has an object of providing a molded article of a composite structure obtained by bonding a polar thermoplastic resin, especially polyacetal, with another resin in a simple manner. According to the present invention, a molded article of a composite structure obtained by bonding a polar thermoplastic resin and a resin containing an aliphatic ester structure as a main component to each other in the state where at least a face at which both of the materials contact each other is in a melted state can be provided.

The invention claimed is: 
     
       1. A composite molded article having a two-layer structure obtained by locating a molded article (a) comprising a polar thermoplastic resin (A) inside a mold, plasticizing an aliphatic ester-structured resin (B) at a temperature higher than a melting point of the thermoplastic resin (A) by 35 to 75° C., injecting the resin (B) to the inside of the mold, and putting the resin (B) into contact with the molded article (a),
 wherein the polar thermoplastic resin (A) is a polyacetal resin, 
 wherein the aliphatic ester-structured resin (B) is at least one selected from polylactic acid (PLA), polyester carbonate (PEC), polybutylene succinate (PBS), and polybutylene succinate adipate (PBSA), 
 wherein said polylactic acid (PLA) has a melting temperature of about 170° C., said polyester carbonate (PEC) has a melting temperature of about 106° C., said polybutylene succinate (PBS) has a melting temperature of about 114° C., and said polybutylene succinate adipate (PBSA) has a melting temperature of about 95° C.; 
 wherein the polar thermoplastic resin (A) contains 50% by volume or less of the aliphatic ester-structured resin (B) beforehand, or the aliphatic ester-structured resin (B) contains 50% by volume or less of the polar thermoplastic resin (A) beforehand, 
 wherein the beforehand amount of the aliphatic ester-structured resin (B) in the polar thermoplastic resin (A) or the beforehand amount of the polar thermoplastic resin (A) in the aliphatic ester-structured resin (B) is such that the aliphatic ester-structured resin (B) adheres to the molded article (a), and 
 wherein the polar thermoplastic resin (A) is polyacetal containing 0.2 to 15 mol (DOL=0.5 to 43 phr) of an oxyalkylene repeat unit having a carbon number of 2 or greater which is represented by the following formula (1) per 100 mol of an oxymethylene repeat unit: 
 
       
         
           
           
               
               
           
         
         where R 0  and R 0 ′ each represent a hydrogen atom, an alkyl group, an organic group containing an alkyl group, a phenyl group, or an organic group containing a phenyl group; and m represents an integer of 2 to 6. 
       
     
     
       2. The composite molded article according to  claim 1 , wherein the molded article (a) is a film, a sheet or a fiber composite. 
     
     
       3. The composite molded article according to  claim 1 , wherein the polar thermoplastic resin (A) contains a part of the aliphatic ester-structured resin (B) beforehand. 
     
     
       4. The composite molded article according to  claim 1 , wherein the aliphatic ester-structured resin (B) contains a part of the polar thermoplastic resin (A) beforehand. 
     
     
       5. A composite molded article having a two-layer structure obtained by locating a molded article (b) comprising an aliphatic ester-structured resin (B) inside a mold, plasticizing a polar thermoplastic resin (A) at a temperature higher than a melting point of the resin (B) by 5 to 95° C., injecting the thermoplastic resin (A) to the inside of the mold, and putting the thermoplastic resin (A) into contact with the molded article (b),
 wherein the polar thermoplastic resin (A) is a polyacetal resin, 
 wherein the aliphatic ester-structured resin (B) is at least one selected from polylactic acid (PLA), polyester carbonate (PEC), polybutylene succinate (PBS), and polybutylene succinate adipate (PBSA), 
 wherein said polylactic acid (PLA) has a melting temperature of about 170° C., said polyester carbonate (PEC) has a melting temperature of about 106° C., said polybutylene succinate (PBS) has a melting temperature of about 114° C., and said polybutylene succinate adipate (PBSA) has a melting temperature of about 95° C.; 
 wherein the polar thermoplastic resin (A) contains 50% by volume or less of the aliphatic ester-structured resin (B) beforehand, or the aliphatic ester-structured resin (B) contains 50% by volume or less of the polar thermoplastic resin (A) beforehand, 
 wherein the beforehand amount of the aliphatic ester-structured resin (B) in the polar thermoplastic resin (A) or the beforehand amount of the polar thermoplastic resin (A) in the aliphatic ester-structured resin (B) is such that the polar thermoplastic resin (A) adheres to the molded article (b), and 
 wherein the polar thermoplastic resin (A) is polyacetal containing 0.2 to 15 mol (DOL=0.5 to 43 phr) of an oxyalkylene repeat unit having a carbon number of 2 or greater which is represented by the following formula (1) per 100 mol of an oxymethylene repeat unit: 
 
       
         
           
           
               
               
           
         
         where R 0  and R 0 ′ each represent a hydrogen atom, an alkyl group, an organic group containing an alkyl group, a phenyl group, or an organic group containing a phenyl group; and m represents an integer of 2 to 6. 
       
     
     
       6. The composite molded article according to  claim 5 , wherein the molded article (b) is a film, a sheet or a fiber composite. 
     
     
       7. The composite molded article according to  claim 5 , wherein the polar thermoplastic resin (A) contains a part of the aliphatic ester-structured resin (B) beforehand. 
     
     
       8. The composite molded article according to  claim 5 , wherein the aliphatic ester-structured resin (B) contains a part of the polar thermoplastic resin (A) beforehand. 
     
     
       9. A method for producing a composite molded article, comprising the steps of:
 locating a molded article (a) comprising a polar thermoplastic resin (A) inside a mold; and 
 plasticizing an aliphatic ester-structured resin (B) at a temperature higher than a melting point of the thermoplastic resin (A) by 35 to 75° C., injecting the resin (B) to the inside of the mold, and putting the resin (B) into contact with the molded article (a) to form a two-layer structure; 
 wherein the polar thermoplastic resin (A) is a polyacetal resin, 
 wherein the aliphatic ester-structured resin (B) is at least one selected from polylactic acid (PLA), polyester carbonate (PEC), polybutylene succinate (PBS), and polybutylene succinate adipate (PBSA), 
 wherein said polylactic acid (PLA) has a melting temperature of about 170° C., said polyester carbonate (PEC) has a melting temperature of about 106° C., said polybutylene succinate (PBS) has a melting temperature of about 114° C., and said polybutylene succinate adipate (PBSA) has a melting temperature of about 95° C.; 
 wherein the polar thermoplastic resin (A) contains 50% by volume or less of the aliphatic ester-structured resin (B) beforehand, or the aliphatic ester-structured resin (B) contains 50% by volume or less of the polar thermoplastic resin (A) beforehand, 
 wherein the beforehand amount of the aliphatic ester-structured resin (B) in the polar thermoplastic resin (A) or the beforehand amount of the polar thermoplastic resin (A) in the aliphatic ester-structured resin (B) is such that the aliphatic ester-structured resin (B) adheres to the molded article (a), and 
 wherein the polar thermoplastic resin (A) is polyacetal containing 0.2 to 15 mol (DOL=0.5 to 43 phr) of an oxyalkylene repeat unit having a carbon number of 2 or greater which is represented by the following formula (1) per 100 mol of an oxymethylene repeat unit: 
 
       
         
           
           
               
               
           
         
         where R 0  and R 0 ′ each represent a hydrogen atom, an alkyl group, an organic group containing an alkyl group, a phenyl group, or an organic group containing a phenyl group; and m represents an integer of 2 to 6. 
       
     
     
       10. The method of  claim 8 , wherein method for producing a composite molded article consists essentially of the steps of:
 locating a molded article (a) comprising a polar thermoplastic resin (A) inside a mold; and 
 plasticizing an aliphatic ester-structured resin (B) at a temperature higher than a melting point of the thermoplastic resin (A) by 35 to 75° C., injecting the resin (B) to the inside of the mold, and putting the resin (B) into contact with the molded article (a) to form a two-layer structure. 
 
     
     
       11. A method for producing a composite molded article, comprising the steps of:
 locating a molded article (b) comprising an aliphatic ester-structured resin (B) inside a mold; and 
 plasticizing a polar thermoplastic resin (A) at a temperature higher than a melting point of the resin (B) by 5 to 95° C., injecting the thermoplastic resin (A) to the inside of the mold, and putting the thermoplastic resin (A) into contact with the molded article (b) to form a two-layer structure; 
 wherein the polar thermoplastic resin (A) is a polyacetal resin, 
 wherein the aliphatic ester-structured resin (B) is at least one selected from polylactic acid (PLA), polyester carbonate (PEC), polybutylene succinate (PBS), and polybutylene succinate adipate (PBSA), 
 wherein said polylactic acid (PLA) has a melting temperature of about 170° C., said polyester carbonate (PEC) has a melting temperature of about 106° C., said polybutylene succinate (PBS) has a melting temperature of about 114° C., and said polybutylene succinate adipate (PBSA) has a melting temperature of about 95° C.; 
 wherein the polar thermoplastic resin (A) contains 50% by volume or less of the aliphatic ester-structured resin (B) beforehand or wherein the aliphatic ester-structured resin (B) contains 50% by volume or less of the polar thermoplastic resin (A) beforehand, 
 wherein the beforehand amount of the aliphatic ester-structured resin (B) in the polar thermoplastic resin (A) or the beforehand amount of the polar thermoplastic resin (A) in the aliphatic ester-structured resin (B) is such that the polar thermoplastic resin (A) adheres to the molded article (b), and 
 wherein the polar thermoplastic resin (A) is polyacetal containing 0.2 to 15 mol (DOL=0.5 to 43 phr) of an oxyalkylene repeat unit having a carbon number of 2 or greater which is represented by the following formula (1) per 100 mol of an oxymethylene repeat unit: 
 
       
         
           
           
               
               
           
         
         where R 0  and R 0 ′ each represent a hydrogen atom, an alkyl group, an organic group containing an alkyl group, a phenyl group, or an organic group containing a phenyl group; and m represents an integer of 2 to 6. 
       
     
     
       12. The method of  claim 11 , wherein method for producing a composite molded article consists essentially of the steps of:
 locating a molded article (b) comprising an aliphatic ester-structured resin (B) inside a mold; and 
 plasticizing a polar thermoplastic resin (A) at a temperature higher than a melting point of the resin (B) by 5 to 95° C., injecting the thermoplastic resin (A) to the inside of the mold, and putting the thermoplastic resin (A) into contact with the molded article (b) to form a two-layer structure.